Shoe with shank spring and stiffener



May 25, 1948.

H. H. JOHNSON SHOEi WITH SHANK SPRING AND STIFFENER Filed Aug. 31

I nventor Fig.5

5 .W wOWA n m 1% H m rum 0 H Q Patented May 25, 1948 SHOE WITH SHANK SPRING AND STIFFENER Harry H. Johnson, Brookline, Mass. Application August 31, 1946, Serial No. 694,289

This invention relates to an improvement in the shoe-making art. The application is a continuation-in-part of my copending application, Serial No. 627,163, filed November 7, 1945, now abandoned.

In conventional footwear such as is commonly worn by men and women in this country, the sole structure comprises a ball portion, a shank portion and a heel portion. The ball portion usually has a substantialy plane tread surface extending from the forward extremity or toe of the sole to the break line or juncture of the ball and shank portions. The shank portion of the sole structure is usually inclined with respect to the ball portion and rises rearwardly to the heel portion which is maintained in a relatively elevated position by a heel member formed on or attached to the under side thereof. The heel member has a tread surface which is in a common plane with the tread surface of the ball portion when the footwear is in its normal or ordinary positiomthat is, the position assumed when a shoe tree is fitted therein or when the footwear is on a foot and the wearer is in an ordinary standing position on a horizontal surface. The sole structure is usually flexible at the break line so that durin walking, running, or the like, the sole flexes at the break line to increase the inclination of the shank portion with respect to the ball portion during a part of each step. Many articles of footwear for men and women are equipped with rigid shank stiffeners which are built into the shank and heel portions of the sole structure and usually extend forward nearly to the break line thus preventing sagging of the arch, helping to keep the heel member at the proper angle to the shank portion of the sole, but not interfering with the flexing of the sole structure at the break line. In ladies shoes, the forward end of the shank stiffener sometimes wears through the outer sole.

Accordin to the present invention, a flexible resilient spring is inserted in the sole structure to underlie the forward portion of the shank stiffener and to extend forward past the break lineand into the ball portion of the sole. This spring is shaped so that its rear portion which underlies the shank stiffener presses upward against the shank stiffener and tends to flex the sole at the break line. The spring also effectually prevents the forward end of the shank stiffener from Wearing or punching through the sole. The physical characteristics of the spring, including strength and resilience, are selected so as to produce the desired degree of upward pressure against the shank stiffener. The shank stiffener 2 Claims. (01. 36-76) flexible spring tends to lift the shank and heel portions of the sole to a steeper inclination with respect to the ball portion, and to operate with the shank stiffener as a compound lever as hereinafter described. When the shoe is worn, the

shank and heel portions of the sole are held against the foot of the wearer at all times, whether the wearer is standing, walking, running or engaging in any other form of activity.

For a more complete understanding of the invention, reference may be made to the following description thereof, and to the drawing, of Which:

Figure 1 is a side elevation of a shoe embodying the invention with the wearers foot therein, a portion being broken away to show in section;

Figure 2 is a bottom plan view of the same;

Figure 3 is a section on the line 33 of Figure 2;

Figure 4 is a perspective view of the spring shown in Figures 1, 2, and 3;

Figures 5 and 6 are perspective views of modified forms of the spring.

The invention is shown in Figure 1 as embodied in a womans shoe of the sling back type consisting of a sole structure It! and an upper l2 which is open at the heel. The sole structure comprises an outer sole 20, an inner sole 22, a sock lining 24, and a heel member 26 which is attached to the heel portion of the outer sole. Between the outer sole and the inner sole is a conventional shank stiffener 30 secured at the heel end by a suitable fastener 32 and extendingfrom the heel portion of the sole forward nearly to the break line 34 of the sole. As indicated in Figure 3, the stiffener 30 is made with a'longitudinal crimp 36 extending for most of its length and forming a longitudinally extending rib therein which materially stiffens the member and makes it substantially rigid. According to the present invention, a flexible resilient spring element 40 is built into the sole structure as indicated in Figures 1, 2, and 3. This element consists of a piece of strong spring metal which is preferably from 0.010" to 0.020" thick, this being somewhat thinner stock than that of which the stiffener 30 is made, and suitably tempered to be highly resilient. In mens shoes and working shoes, heavier stock up to 0.030" or more can be used. The element may be cut from a strip of spring steel or other spring metal or may be cut out of a sheet of such metal, and is of sufficient length to extend from a point well forward of the break line in the 3 ball portion of the sole to a point in the shank portion of the sole near'the heel. If, as illustrated in Figure 3, the shank stiffener 30 is made with a longitudinal rib 36, the portion of the 4' foot often occurs. Since the forward end portion of the shank stifiener is approximately midway between the adjacent side edges of the sole, it tends to support and elevate the longitudinal arch spring 49 which underlies the ribbed portion of 5 of the foot. Thus the shoe in which the spring 7 the shank stifiener is also preferably crimped as at '52 so that a part of the spring 58 has a longitudinal rib fitting against the rib 36 of the shank stiffener 353. This helps to maintain the spring &0 in its proper position within the sole structure. In assembling the sole structure on a last, the forward portion 65 of the spring 40 may be se-j i cured to the ball portion of the inner sole 22b1 any suitable adhesive or by a fastenersuch-asa 40 is built in underneath the shank stiiiener is f not only comfortable to wear but also results in corrective support of fallen or sagging arches.

Instead of being shaped, as illustrated in Figure 10 4, from a sheet of spring metal, the spring may This iidrm is desirable in mens shoes which have con-.

be forked as illustrated at in Figure 5.

, ssiiie jahle width, the forked shape it of the forr d portion permitting a certain amount of tack it. The forwar en p r of h P smtwistmg action in the spring which provides a may also be adhesively secured to theouter sole; if desired. 7

As shown in Figure l, the-spring lil is made v with a bend as at it so that the rear portionofthe spring is inclined with respect to the forward po i t e an le of i lin tion beine m ri l y steeper than the angl ofjinclination of the shank of the. solestructure with respect to theball portion ottlf esole structure when the shoe is in its o dinary normalposi mn. that ,is, which it assumes when itisbeing worn and when the wearer. is in. an ordinary. standin position with the tread surfaces of both the sole and heel of. the shoe resting on the ground.

@ ;.d,egree,of freedom of action of the sole structure.

A simplerjorm of spring is shown in Figure 6, this form consisting of a strip 32 of spring steel with an intermediate bend and, if desired, a crimped rib 42 in its rear portion to nest with the ,crimpedrib 36 of the shank stifiener 3 3.

To fastenthe forward end portion of the spring.

4].,or48tothe innersole 22 'or outer sole, a suit.-

able adhesive maybe used, or,.as indicated at e the po l on 2 5 49 in Figure 6, a piece'of adhesive tape may be wrapped about the forward portion. Any of the springsshownron the drawing ,canbe assembled in the sole structure without any fastening means,

buttheuse of some fastening means is convenient,

.Si'nc h anel of in lin i n f h ar'po 3 0 to. keep the spring properly in place when the timer the sp n is wit spect t the forward portionthereof is steeperthan the corresponding angle in the shoe itself, jtheeffect of installing the spring it in the shoe structurein th mann outer sole 201s being applied 7 Iclaim:

.1. In an article ofiootwear, a sole structure.

which bas ball, shank and heel portions, a rigid hQWI lF 1 t i le a the sh nk a dhe e5 shank stiffener secured at one end to the heel porportions of the sole structure toasteeper than usualinclination with respect tothe ball portion of the sole. The amount of bend. of the spring iii) is prefera lysufiicient ,tocausfi theshank and tion .of thesole structure. and extending forward on the shank portion, and a flexible" resilient I member; in said ball andshank portions, the rear partof said member underlying the forward part 116,61 D q gf-the sole m an angle of 40 of said shank stifiener, the forward end of said portions of the shoe against the foot of member extending into the ball portion of the solestructure said member having a bend be-.

tween-its iorward and .rear parts and being. of

sucha s'trength as to resiliently maintain said shankandheelportions of the sole structure at amaterially steeper angle of inclination with respectito said ball portion than the corresponding angle-in .an ordinary ishoe of the same size andstyle-when ofi thefoohwhereby Whensaid ffoot thefiblewstrllcture usually 1959s 09m?! i the 5.0 wear is worn saidjflexible resilient member intent ,of the wearer, when the foot is flexed as walking and the like, 7

l .Thejsprin 49 alsohas an additional functi n which is highly important, especially to those who The upward pressureof the rear portion ofthe spring-Ail against the forward portion of the shank stiffener?!) which it underlies tends to rockthe shank stiffener upward about its rear end as a herentlypresses upwardagainst said shank stiffener so asto hold the shank and heel portions of the solestructure against the root at all times during walking and the like and inherently tends r e n v toward-fallenfirchfisfir flatfe-et 'to elevate the shank'and heel portions of the sole structure.

2..In'an article of footwear, a sole structure 1 ful ru Th forward portion Of-ths shank stifif c0 and the flexible resilient member is formed with 'ener, in turn, presses upward against the portion,

of the inhersole adjacen t t e r ak lin n thus resiliently-supports the archof the foot at a somewhere-sag ing of the natural arch of the a. complemental rib in the part thereof underlying the shankstifiener. 7 V f 7 HARRY H. JOHNSON. 

